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[4.2.y-ckt,02/98] tipc: fix nullptr crash during subscription cancel

Message ID 1458084692-23100-3-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa March 15, 2016, 11:29 p.m. UTC 
4.2.8-ckt6 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>

commit 4de13d7ed6ffdcbb34317acaa9236f121176f5f8 upstream.

commit 4d5cfcba2f6e ('tipc: fix connection abort during subscription
cancel'), removes the check for a valid subscription before calling
tipc_nametbl_subscribe().

This will lead to a nullptr exception when we process a
subscription cancel request. For a cancel request, a null
subscription is passed to tipc_nametbl_subscribe() resulting
in exception.

In this commit, we call tipc_nametbl_subscribe() only for
a valid subscription.

Fixes: 4d5cfcba2f6e ('tipc: fix connection abort during subscription cancel')
Reported-by: Anders Widell <anders.widell@ericsson.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 net/tipc/subscr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
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Patch

diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c
index 69ee2ee..f9ff73a 100644
--- a/net/tipc/subscr.c
+++ b/net/tipc/subscr.c
@@ -296,7 +296,8 @@  static void tipc_subscrb_rcv_cb(struct net *net, int conid,
 	if (tipc_subscrp_create(net, (struct tipc_subscr *)buf, subscrb, &sub))
 		return tipc_conn_terminate(tn->topsrv, subscrb->conid);
 
-	tipc_nametbl_subscribe(sub);
+	if (sub)
+		tipc_nametbl_subscribe(sub);
 }
 
 /* Handle one request to establish a new subscriber */